mattwebdev on "how to arrange the text width in the 2014 theme?"

Hi there.

The code that is controling the content width of your theme is:

.site-content .entry-header, .site-content .entry-content, .site-content .entry-summary, .site-content .entry-meta, .page-content {
margin: 0 auto;
max-width: 474px;
}

You can see it has been set to a max-width of 474px, and the margin: 0 auto is what is centering it. You could simply override the max-width value to achieve the look you're after.

Probably best to do so in a child theme (http://codex.wordpress.org/Child_Themes).